Kakano Road "Make Safe" Demolition
Location: Kakano Road, Westgate, Auckland
Project Duration: April - June 2023
Project Value: $115,000
Overview
The Kakano Road "Make Safe" demolition was a high-risk project undertaken by Henderson Demolition Ltd in Westgate, Auckland, during the months of April to June 2023. This urgent project involved the removal of a collapsed suspended concrete slab and associated damaged structural steel. With a project value of $115,000, Henderson Demolition was responsible for safely dismantling the compromised structure, addressing several complex challenges, including tight space restrictions, the risk of further structural collapse, and the need to salvage materials wherever possible.
Project Challenges
This project presented a number of unique challenges:
Inherently Unsafe Site: The site was dangerous due to the partial collapse of a suspended concrete slab and its supporting structural steel.
Deformed I-Beams: Working under deformed suspended I-beams increased the risk of further collapse, necessitating extreme caution during all operations.
Restricted Machinery Use: The limited space on-site restricted the types of machinery and equipment that could be safely deployed.
Salvage Requirements: Strict requirements to recover any usable materials added further complexity to the methodology.
External Oversight: The works were initiated in response to a notifiable event reported to WorkSafe New Zealand, requiring ongoing oversight from WorkSafe, SiteSafe, and external consultants. This involved detailed planning and regular reviews to ensure all safety and compliance measures were followed.
Tight Deadline: The demolition needed to be completed within a short time frame to avoid delays to the wider construction project, creating additional pressure to ensure the work was carried out efficiently and safely.
Methodology
Pre-deconstruction Planning and Review:
Prior to beginning the demolition works, a detailed methodology was developed in consultation with engineers and external safety consultants to ensure that the structure could be dismantled safely. The plan included several hold points, where engineers reviewed the proposed actions and temporary stabilisation works before allowing the project to proceed.
Key components of the pre-deconstruction process included:
Installing shore loading and bracing in key areas to ensure structural stability during the deconstruction.
Conducting a thorough review of all temporary works and bracing by engineers and other stakeholders before beginning dismantling operations.
Deconstruction and Removal:
Once the site was stabilised, Henderson Demolition initiated a carefully planned demolition process to remove the collapsed concrete slab and the damaged structural steel. The work was carried out in a controlled, phased manner, with safety and structural integrity at the forefront of all decisions.
Pre-start Meetings: Before any major work commenced, a pre-start meeting was held with the demolition team and all contractors involved to review the method, Job Safety Analysis (JSA), and Safe Work Method Statements (SWMS). This ensured that all workers were fully aware of the plan and the safety requirements.
Temporary Shore Loading and Bracing: Additional shore loading and bracing were installed to stabilise key beams and grid lines before the deconstruction process began. This was essential for safely removing the damaged concrete slab and steel without further collapse.
Steel and Concrete Removal:
Two excavators were used to carefully dismantle the collapsed steel and concrete. One excavator held sections of the collapsed steel in place, while another, equipped with a shear attachment, cut the steel into smaller, manageable pieces for removal.
A second excavator, fitted with a pulveriser attachment, was used to slowly break apart the collapsed concrete floor, while another machine held the sections in place to prevent any destabilisation during the process.
Reinforcement Removal: The reinforcement of the insuiti slab was removed systematically, allowing safe access to remove the shore loading towers between grid lines. This also reduced the weight of the remaining structure, enabling the careful removal of the collapsed sections while separating salvageable materials for reuse.
Waste Disposal: Once the concrete and steel were dismantled and lowered safely to the ground, the materials were loaded onto trucks and transported to appropriate disposal facilities. All waste handling followed strict environmental guidelines to ensure proper disposal.
Safety Considerations
Given the inherent dangers of this project, safety was the top priority at every stage. The risk of further collapse required a cautious, methodical approach, with no sudden movements from machinery that could destabilise the structure. Temporary shore loading and bracing were continually reviewed by engineers, and all demolition activities were carried out at a controlled, slow pace.
In addition to Henderson Demolition's stringent safety protocols, the project was overseen by external safety bodies, including WorkSafe and SiteSafe. Regular inspections and hold points were established to ensure compliance with all safety regulations and to confirm the integrity of the temporary works before proceeding with each stage of the demolition.
Project Outcome
Despite the significant challenges posed by the unsafe site conditions, restricted space, and the need to salvage materials, Henderson Demolition successfully completed the project within the scheduled timeframe. The "Make Safe" demolition was carried out to the highest safety and compliance standards, ensuring the safety of workers and minimising delays to the overall construction project.
Henderson Demolition’s ability to manage the complexities of this project demonstrates our expertise in high-risk demolitions. By prioritising safety and sustainability, we were able to navigate the unique challenges of the Kakano Road demolition while ensuring a successful and timely outcome.
